Browse Prior Art Database

Multipoint without Address

IP.com Disclosure Number: IPCOM000045101D
Original Publication Date: 1983-Jan-01
Included in the Prior Art Database: 2005-Feb-06
Document File: 2 page(s) / 34K

Publishing Venue

IBM

Related People

Elie, G: AUTHOR [+3]

Abstract

The purpose of this system is to design an interface for easily attaching terminals to a common bus without requiring the installer to define an address or any other form of identification of the terminals.

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Multipoint without Address

The purpose of this system is to design an interface for easily attaching terminals to a common bus without requiring the installer to define an address or any other form of identification of the terminals.

The transmit and receive sections of each terminal are referenced E and R, respectively. Devices E and R of each terminal are attached to the bus through a dual switch (S, S') as shown in the figure. It should be noted that within each terminal a strap is used for connecting together the position (1) of both switches. The possible states of each terminal are: receive mode, transmit mode, and standby mode.

The controller is initially loaded with the number of associated terminals. Initially, all the switches have been set to position (1). When the controller starts polling, the first terminal is the only one to be made aware of that through switches S1 and S'1 set in position (1). This terminal may start a transaction with the controller. At the transaction end, the controller sends a switch request, and the terminal switches to position (2). In this position, R1 is still connected to the bus while E1 is disconnected therefrom. The first terminal then waits for a general reset request and ignores any other message. The continuity of the bus is thus established up to the second terminal (E2, R2). The same procedure occurs with this terminal, and so on up to the last terminal.

The controller having initially been loaded with the number...